Drug delivery devices which comprise a removable pen cap are known for example from EP 1 007 115 B1.
Drug delivery devices are to be used in case of a disease where a permanent medication is needed, like for example diabetes. These devices are very comfortable in usage for self-administration of insulin or other medicinal products by a patient. Some reusable pen-type injectors are described in EP 1 923 085 A1 or in EP 0 554 995 A1.